The purpose of this project is to investigate the molecular structure of fibrous proteins and proteoglycans, and to study intracellular gelation of Hemoglobin S. The structural information obtained will be correlated with function. Areas of present interest are 1) Molecular structure and dynamics of collagen. 13C and 2H magnetic resonance techniques are being used to study the structure and interactions in collagen fibers. 2) Proteoglycan structure. 13C magnetic resonance is also being used to study the molecular mobility of the polysaccharide and protein chains in the chick limb bud proteoglycan monomer. 3) 13C magnetic resonance is being used to study the extent and mechanism of hemoglobin S gelation in erythrocytes. For these studies, magnetic resonance spectrometers have been assembled which give 2H, 13C and 31P spectra of solids. High power decoupling, cross-polarization, magic angle spinning, and solid echo experiments are all performed.